Discussion
Injection molding is typically used to make plastic parts. If the pressure at the gate is monitored as a function of time during the injection of a thermoplastic polymer, identify the profile that best describes this event.
Answer: C
The best description is profile P.
During injection the pressure at the gate goes through three stages:
- Filling: as melt flows into the cavity the pressure rises gradually, since the flow length and resistance keep increasing.
- Packing: once the cavity is full the melt is compressed and extra material is packed in to make up for shrinkage, so the pressure climbs steeply to its peak.
- Holding and cooling: the gate freezes, the part cools and shrinks, and the pressure decays back toward zero.
Profile P shows exactly this: a first rise, a sharper rise to a peak, and then decay to zero. Q and R begin with an instant jump that ignores the filling stage, and S levels off without ever decaying, as if the part never cooled.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development